A Costco wholesale store in South San Francisco, Calif., is recalling nearly 40,000 pounds of rotisserie chicken products because the food may be linked to an outbreak of salmonella poisoning that now has sickened more than 300 people in 20 states, federal health officials said early Saturday.

The Costco store at 1600 El Camino Real is recalling 8,730 Kirkland Signature Foster Farms rotisserie chickens and 313 units of Kirkland Farm rotisserie chicken soup, rotisserie chicken leg quarters and rotisserie chicken salad, according to a notice issued by the U.S. Department of Agriculture's Food Safety and Inspection Service. The products were sold directly to consumers between Sept. 11 and Sept. 23.

The rotisserie chickens may have been contaminated with a type of Salmonella heidelberg rarely found in the United States, FSIS officials said. The strain is linked to an ongoing food poisoning outbreak associated with three Foster Farms poultry plants in Fresno and Livingston, Calif. The USDA issued a public health alert for products from the plant on Monday, but on Thursday agreed that the facilities could remain open if the company made promised food safety fixes.

At least 317 people in 20 states have been sickened by the outbreak since March, according to an updated notice from the Centers for Disease Control and Prevention. Most of the cases have been in California, where 232 people have been reported ill. It is the second outbreak of salmonella Heidelberg tied to Foster Farms in less than a year. A previous outbreak sickened 134 people in 13 states.

Some of the seven strains of salmonella detected in the outbreak are drug-resistant, which has created hard-to-treat infections in some patients. About 42 percent of victims in the outbreak have been hospitalized, twice the typical rate for salmonella infections.

The rotisserie chicken recall is limited to the single store, Craig Wilson, Costco's vice president for food safety, told NBC News on Saturday. One cooked bird tested positive for the rare salmonella strain, Wilson said.

Wilson said the firm and federal officials are investigating how cooked chicken could have led to 18 to 20 reported illnesses among Costco customers who ate chicken from the South San Francisco store. Costco rotisserie chickens are routinely cooked to 180 degrees Fahrenheit, Wilson said, higher than the 165 degrees required to kill salmonella bacteria.

"I don't know if we're looking at an enormous bio-load," he said, referring to high levels of salmonella bacteria. "Or was it possibly cross-contaminated?"

The Kroger Co., a large chain of grocery stores, removed the affected Foster Farms raw chicken products from store shelves earlier this week and notified customers that they may have bought contaminated meat. The company removed products from its Fred Meyer, Fry's, King Soopers/City Market, Ralphs, Food 4 Less, Smith's in southern Nevada and New Mexico and QFC stores and warehouses, officials said in a statement. Not all Foster Farms products were affected by the public health alert, so some chicken remains on store shelves, officials said.

Foster Farms officials have declined to issue voluntary recalls for their chicken products, saying that USDA continued to inspect the products daily and that the raw chicken is safe if handled properly and cooked to 165 degrees Fahrenheit, which will kill the bacteria.

Salmonella heidelberg can cause illness that may be life-threatening in people with weak immune systems such as children, the elderly and those with cancer or HIV infection. Most common symptoms include diarrhea, abdominal cramps and fever within eight hours to three days after eating the contaminated product. Chills, headache, nausea and vomiting can last up to a week.

Foster Farms is a West Coast poultry producer with plants in Oregon, Washington, California and Alabama.

JoNel Aleccia is a senior health writer with NBC News. Follow her on Twitter at @JoNel_Aleccia orsend her an email.